Deep Dive · XiaoHu Explains

Twelve Rules of Harness Engineering: A Google Principal Engineer's Year of Practice, Distilled Into Processes and Templates You Can Use Today

The core move is counterintuitive: freeze the chosen model and Agent completely — don't tune a single parameter, just change what surrounds it: context and tools.
What this is

Twelve rules, and a word that gets mistranslated

Let's get the word right first. Harness here means tack — bridle, reins, horseshoes, straps, the whole rig — and the repo's description opens with a horse emoji. It's easy to read as "restraint," which points exactly the wrong way.

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